In patients who are naive to anti-retroviral therapy or who have received less than 16 weeks of ZDV study will compare the safety, tolerance, and efficacy based on clinical endpoints of: 1) ZDV; 2) ZDV + ddC; 3) ZDV + saquinavir and 4) ZDV + ddC + saquinavir. The purpose of this study is to test if saquinavir (proteinase inhibitor) will interfere with the growth of HIV in the body and to test whether saquinavir is safe to take for at least 80 weeks.